Clinical Benefit of Tyrosine Kinase Inhibitors in Advanced Lung Cancer with EGFR-G719A and Other Uncommon EGFR Mutations

Current management of uncommon EGFR mutations in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations are frequently implicated in non-small cell lung cancer (NSCLC). Though these typically involve exon 19 in-frame deletions or L858R mutations in exon 21, uncommon EGFR mutations comprise 10-15 % of all EGFR mutations. These most frequently include G719X mutations in exon 18, L861Q mutations in exon 21, S768I mutations in exon 20, and in-frame insertions and/or duplications in exon 20. It is crucial to understand these distinct variants and their specific responses to active treatment options to optimize care. In this review, we discuss these uncommon mutations in depth and dissect the current literature regarding their treatment outcomes and subsequent evidence-based management guidelines.

Successful therapy of a critically ill non-small cell lung cancer patient with compound mutations in EGFR G719X and S768I genes using furmonertinib: A case report

Background

Somatic mutations in epidermal growth factor receptor (EGFR) genes, such as G719X and S768I, and tyrosine kinase inhibitors (TKIs) have been confirmed to be promising for developing new targeted therapies against advanced non-small-cell lung cancer (NSCLC). The G719X and S768I mutations are uncommon and often occur in the form of compound mutations. However, the efficacy of furmonertinib in patients with these uncommon compound mutations has not yet been elucidated.

Case presentation

In this study, the G719X/S768I compound mutations were detected in a critically ill NSCLC patient. This patient received furmonertinib for 14 months and successfully responded to the treatment. The present case report highlights the ideal clinical response, with ongoing follow-up.

Conclusion

We report the successful treatment of a critically ill NSCLC patient carrying rare compound EGFR G719X and S768I mutations using furmonertinib. To the best of our knowledge, this is the first reported case of a successful furmonertinib treatment of compound EGFR G719X and S768I mutations. Furmonertinib, a third-generation EGFR-TKI, may be effective in controlling the EGFR G719X and S768I compound mutations in NSCLC.

Targeted therapies in non-small cell lung cancer: present and future

Lung cancer is the leading cause of malignancy-related death in the United States and the second most common cancer diagnosis worldwide. In the last two decades, lung cancer treatment has evolved to include advances in the development of mutation-based targeting, immunotherapy, radiation therapy, and minimally invasive surgical techniques. The discovery of lung cancer as a molecularly heterogeneous disease has driven investigation into the development of targeted therapies resulting in improved patient outcomes. Despite these advances, there remain opportunities, through further investigation of mechanisms of resistance, to develop novel therapeutics that better direct the personalization of lung cancer therapy. In this review, we highlight developments in the evolution of targeted therapies in non-small cell lung cancer, as well as future directions shaped by emerging patterns of resistance.

EGFR exon 20 insertion mutations and ERBB2 mutations in lung cancer: a narrative review on approved targeted therapies from oral kinase inhibitors to antibody-drug conjugates

Background and Objective

This review will provide an overview of EGFR and ERBB2 mutations in non-small-cell lung cancer (NSCLC) with a focus on recent clinical approvals.

Methods

We obtained data from the literature in accordance with narrative review reporting guidelines.

Key Content and Findings

EGFR mutations are present in up to 15-20% of all NSCLCs; amongst these, 10% correspond to kinase domain insertions in exon 20. Structurally similar, ERBB2 (HER2) mutations occurs in 1-4% of NSCLCs, mostly consisting of insertions or point mutations. The majority of EGFR exon 20 insertions occur within the loop following the regulatory C-helix and activate the kinase domain of EGFR without generating a therapeutic window to gefitinib, erlotinib, afatinib, dacomitinib or osimertinib. Mobocertinib represents a novel class of covalent EGFR inhibitors with a modest therapeutic window to these mutants and induces anti-tumor responses in a portion of patients [at 160 mg/day: response rate of <30% with duration of response (DoR) >17 months and progression-free survival (PFS) of >7 months] albeit with mucocutaneous and gastrointestinal toxicities. The bi-specific EGFR-MET antibody amivantamab-vmjw has modest but broad preclinical activity in EGFR-driven cancers and specifically for EGFR exon 20 insertion-mutated NSCLC has response rates <40% and PFS of <8.5 months at the cost of both infusion-related plus on-target toxicities. Both drugs were approved in 2021. The clinical development of kinase inhibitors for ERBB2-mutated NSCLC has been thwarted by mucocutaneous/gastrointestinal toxicities that preclude a pathway for drug approval, as the case of poziotinib. However, the activation of ERBB2 has allowed for repurposing of antibody-drug conjugates (ADCs) that target ERBB2 with cytotoxic payloads. The FDA approved fam-trastuzumab deruxtecan-nxki in 2022 for NSCLC based on response rate of >55%, DoR >9 months, PFS >8 months and manageable adverse events (including cytopenias, nausea and less commonly pneumonitis). Other therapies in clinical development include sunvozertinib and zipalertinib, among others. In addition, traditional cytotoxic chemotherapy has some activity in these tumors.

Conclusions

The approvals of mobocertinib, amivantamab, and trastuzumab deruxtecan represent the first examples of precision oncology for EGFR exon 20 insertion-mutated and ERBB2-mutated NSCLCs.

EGFR exon 19 insertion EGFR-K745_E746insIPVAIK and others with rare XPVAIK amino-acid insertions: Preclinical and clinical characterization of the favorable therapeutic window to all classes of approved EGFR kinase inhibitors

BACKGROUND

The epidermal growth factor receptor (EGFR)-K745_E746insIPVAIK and others with XPVAIK amino-acid insertions are exon 19 insertion mutations, which, at the structural modeling level, resemble EGFR tyrosine kinase inhibitor (TKI)-sensitizing mutants. An important unmet need is the characterization of therapeutic windows plus clinical outcomes of exon 19 XPVAIK amino-acid insertion mutations to available EGFR TKIs.

METHODS

We used preclinical models of EGFR-K745_E746insIPVAIK and more typical EGFR mutations (exon 19 deletion, L858R, L861Q, G719S, A763_Y764insFQEA, other exon 20 insertion mutations) to probe representative 1st (erlotinib), 2nd (afatinib), 3rd generation (osimertinib), and EGFR exon 20 insertion active (mobocertinib) TKIs. We also compiled outcomes of EGFR exon 19 insertion mutated lung cancers-from our institution plus the literature-treated with EGFR TKIs.

RESULTS

Exon 19 insertions represented 0.3-0.8% of all EGFR kinase domain mutation in two cohorts (n = 1772). Cells driven by EGFR-K745_E746insIPVAIK had sensitivity to all classes of approved EGFR TKIs when compared to cells driven by EGFR-WT in proliferation assays and at the protein level. However, the therapeutic window of EGFR-K745_E746insIPVAIK driven cells was most akin to those of cells driven by EGFR-L861Q and EGFR-A763_Y764insFQEA than the more sensitive patterns seen with cells driven by an EGFR exon 19 deletion or EGFR-L858R. The majority (69.2%, n = 26) of patients with lung cancers harboring EGFR-K745_E746insIPVAIK and other mutations with rare XPVAIK amino-acid insertions responded to clinically available EGFR TKIs (including icotinib, gefitinib, erlotinib, afatinib and osimertinib), with heterogeneous periods of progression-free survival. Mechanisms of acquired EGFR TKI resistance of this mutant remained underreported.

CONCLUSIONS

This is the largest preclinical/clinical report to highlight that EGFR-K745_E746insIPVAIK and other mutations with exon 19 XPVAIK amino-acid insertions are rare but sensitive to clinically available 1st, 2nd, and 3rd generation as well as EGFR exon 20 active TKIs; in a pattern that mostly resembles the outcomes of models with EGFR-L861Q and EGFR-A763_Y764insFQEA mutations. These data may help with the off-label selection of EGFR TKIs and clinical expectations of outcomes when targeted therapy is deployed for these EGFR mutated lung cancers.

Structure-Guided Strategies of Targeted Therapies for Patients with EGFR-Mutant Non-Small Cell Lung Cancer

Oncogenic mutations within the EGFR kinase domain are well-established driver mutations in non-small cell lung cancer (NSCLC). Small-molecule tyrosine kinase inhibitors (TKIs) specifically targeting these mutations have improved treatment outcomes for patients with this subtype of NSCLC. The selectivity of these targeted agents is based on the location of the mutations within the exons of the EGFR gene, and grouping mutations based on structural similarities has proved a useful tool for conceptualizing the heterogeneity of TKI response. Structure-based analysis of EGFR mutations has influenced TKI development, and improved structural understanding will inform continued therapeutic development and further improve patient outcomes. In this review, we summarize recent progress on targeted therapy strategies for patients with EGFR-mutant NSCLC based on structure and function analysis.

Real-world global data on targeting epidermal growth factor receptor mutations in stage III non-small-cell lung cancer: the results of the KINDLE study

Background:

Tyrosine kinase inhibitors (TKIs) are the standard of care for resectable and metastatic non-small-cell lung cancer (NSCLC) harbouring epidermal growth factor receptor (EGFR) mutations (EGFRm). We describe the real-world practice of EGFRm testing, prevalence, treatment and outcomes in EGFRm stage III NSCLC from a multi-country, observational study.

Methods:

The KINDLE study retrospectively captured diagnostic information, treatments and survival outcomes in patients with stage III NSCLC from January 2013 to December 2017. Baseline characteristics and treatments were described and real-world outcomes from initial therapy were analysed using Kaplan–Meier methods.

Results:

A total of 3151 patients were enrolled across three regions: Asia (n = 1874), Middle East and North Africa (MENA) (n = 1046) and Latin America (LA) (n = 231). Of these, 1114 patients (35%) were tested for EGFRm (46% in Asia, 17% in MENA and 32% in LA) and EGFRm was detected in 32% of tested patients (34.3% in Asia, 20.0% in MENA and 28.4% in LA). In a multi-variate analysis, overall EGFRm patients treated with EGFR-TKI monotherapy as initial treatment, without any irradiation, had twice the risk of dying (hazard ratio: 1.983, 95% confidence interval: 1.079–3.643; p = 0.027) versus any other treatment. Finally, unresectable patients with EGFRm NSCLC who received concurrent chemoradiotherapy (cCRT) as initial therapy had longer overall survival (OS) compared with their counterparts who only received TKI monotherapy without any irradiation (48 months versus 24 months; p < 0.001).

Conclusion:

The KINDLE study showed that a minority of stage III NSCLC patients were tested for EGFRm. Patients with EGFRm with unresectable NSCLC had similar outcomes from cCRT as initial therapy compared with EGFR wild type with a trend in OS favouring the EGFRm group. Outcomes with EGFR-TKI monotherapy as initial therapy, without any irradiation, were worse. The ongoing LAURA study (NCT03521154) will help define the role of EGFR-TKIs in EGFRm stage III NSCLC treated with cCRT.

Trial Registration:

NCT03725475.

High dose osimertinib in patients with advanced stage EGFR exon 20 mutation-positive NSCLC: Results from the phase 2 multicenter POSITION20 trial

INTRODUCTION

Patients with life-threatening advanced non-small cell lung cancer (NSCLC) who harbor an exon 20 deletion and/or insertion mutation (EGFRex20 + ) have limited effective treatment options. The high dose 3rd generation tyrosine kinase inhibitor (TKI) osimertinib shows promising in vitro activity in EGFRex20 + NSCLC tumors.

METHODS

The POSITION20 is a single arm phase II, multicenter study investigating 160 mg osimertinib in patients with EGFRex20+, T790M negative NSCLC. We allowed patients to be treatment naïve and to have asymptomatic brain metastases. The primary endpoint was overall response rate (ORR). Secondary outcomes were duration of response (DoR), progression free survival (PFS), overall survival (OS), and treatment related adverse events (trAEs).

RESULTS

From June 2018 to October 2021, 25 patients were enrolled across five centers in the Netherlands. The median age was 70 years (range, 47-87), 20 patients (80%) were women, and the median number of previous lines of therapy was 1 (range, 0-3). The exon 20 mutations were clustered between A763 and L777. The most common exon 20 mutations were p.(N771_H773dup) (n = 3) and p.(A767_V769dup) (n = 3). The ORR was 28% (95% CI, 12-49%), including seven partial responses, with a median DoR of 5.3 months (range, 2.7-27.6). The median PFS was 6.8 months (95% CI, 4.6-9.1) and the median OS was 15.2 months (95% CI, 14.3-16.0). The most common trAEs were diarrhea (72%), dry skin (44%), and fatigue (44%). The primary reason for discontinuation was progressive disease in 14 patients (56%).

CONCLUSION

The POSITION20 study showed modest antitumor activity in patients with EGFRex20 + NSCLC treated with 160 mg osimertinib, with a confirmed ORR of 28% and acceptable toxicity.

Two Unusual Mutations in the Epidermal Growth Factor Receptor Gene in a Patient With Lung Adenocarcinoma

Adenocarcinoma (ADC) of the lung is the most frequent pathology corresponding to non-small cell lung cancer (NSCLC). The advent of target therapy and the discovery of drugs that block signaling pathways related to cellular events involved in the progression of the disease have led to a better prognosis in cases of ADC. Some of the targeted therapy focuses on the blockade of epidermal growth factor receptor (EGFR), targeting mutations in exon 19 and 21, with favorable clinical outcomes. However, there is limited evidence with respect to unusual mutations as in exon 18 (g719x) and 20 (s768). In this report, we present a case of a 65-year-old female with two unusual mutations in the EGFR gene, in exon 18 (g719x) and 20 (s768i), without central nervous system (CNS) involvement; these mutations are typically resistant to standard therapy. We decided to administer osimertinib because of its favorable toxicity profile and with a view to preventing future CNS relapse.

A Rare Presentation of a Non-Asian Female With Metastatic Non-small-cell Lung Cancer Harboring EGFR L747P Mutation With Clinical Response to Multi-targeted Epigenetic and EGFR Inhibition

BACKGROUND

Activating mutations of the epidermal growth factor receptor (EGFR) gene have been utilized to predict the effectiveness of EGFR tyrosine kinase inhibitor (TKI) therapy. The most common EGFR mutations are exon 19 deletion and exon 21-point mutation, which are sensitive to EGFR TKI. However, rare/complex EGFR mutations still exist, data of which are scarce and controversial. Hence, their role in response to standard therapy remains uncertain.

CASE REPORT

We present the case of a patient diagnosed with stage IV lung adenocarcinoma for whom standard chemotherapies, including platinum agents, had failed. The patient was found to have an EGFR exon 19 (L747P) mutation, as evident in her liquid biopsy. This alteration has not been described before in the literature on non-Asian females. Data from the current case study highlight the aggressive nature of this type of EGFR mutation as indicated by the complete resistance to erlotinib. Using standard first-generation EGFR inhibitors in treating this point mutation was considered inadequate. However, this patient showed a substantial response when treated with erlotinib combined with epigenetic therapies, consisting of DNA methyltransferase and histone deacetylase inhibitors. For more than 8 years, the patient has been responding to combination therapy with a normal quality of life.

CONCLUSION

This case represents a possible novel approach to reducing resistance in patients harboring this rare EGFR mutation which may translate to better outcomes.

A Nationwide Study on the Impact of Routine Testing for EGFR Mutations in Advanced NSCLC Reveals Distinct Survival Patterns Based on EGFR Mutation Subclasses

EGFR mutation analysis in non-small-cell lung cancer (NSCLC) patients is currently standard-of-care. We determined the uptake of EGFR testing, test results and survival of EGFR-mutant NSCLC patients in the Netherlands, with the overall objective to characterize the landscape of clinically actionable EGFR mutations and determine the role and clinical relevance of uncommon and composite EGFR mutations. Non-squamous NSCLC patients diagnosed in 2013, 2015 and 2017 were identified in the Netherlands Cancer Registry (NCR) and matched to the Dutch Pathology Registry (PALGA). Overall, 10,254 patients were included. Between 2013-2017, the uptake of EGFR testing gradually increased from 72.7% to 80.9% (p < 0.001). Multi-gene testing via next-generation sequencing (increased from 7.8% to 78.7% (p < 0.001), but did not affect the number of detected EGFR mutations (n = 925; 11.7%; 95% confidence interval (CI), 11.0-12.4) nor the distribution of variants. For patients treated with first-line EGFR inhibitors (n = 651), exon 19 deletions were associated with longer OS than L858R (HR 1.58; 95% CI, 1.30-1.92; p < 0.001) or uncommon, actionable variants (HR 2.13; 95% CI, 1.60-2.84; p < 0.001). Interestingly, OS for patients with L858R was similar to those with uncommon, actionable variants (HR 1.31; 95% CI, 0.98-1.75; p = 0.069). Our analysis indicates that grouping exon 19 deletions and L858R into one class of 'common' EGFR mutations in a clinical trial may mask the true activity of an EGFR inhibitor towards specific mutations.

Precision Medicine in Oncology: A Review of Multi-Tumor Actionable Molecular Targets with an Emphasis on Non-Small Cell Lung Cancer

Precision medicine is essential for the modern care of a patient with cancer. Comprehensive molecular profiling of the tumor itself is necessary to determine the presence or absence of certain targetable abnormalities or biomarkers. In particular, lung cancer is a disease for which targetable genomic alterations will soon guide therapy in the majority of cases. In this comprehensive review of solid tumor-based biomarkers, we describe the genomic alterations for which targeted agents have been approved by the United States Food and Drug Administration (FDA). While focusing on alterations leading to approvals in a tumor-agnostic fashion (MSI-h, TMB-h, NTRK) and on those alterations with approvals in multiple malignancies (BRAF, ERBB2, RET, BRCA, PD-L1), we also describe several biomarkers or indications that are likely to lead to an approved drug in the near future (e.g., KRAS G12C, PD-L1 amplification, HER2 overexpression in colon cancer, HER2 mutations in lung cancer). Finally, we detail the current landscape of additional actionable alterations (EGFR, ALK, ROS1, MET) in lung cancer, a biomarker-rich malignancy that has greatly benefitted from the precision oncology revolution.

Afatinib as first-line treatment in patients with EGFR-mutated non-small cell lung cancer in routine clinical practice

Background:

Lung cancer is a leading cause of cancer-related death in Germany and worldwide. Non-small cell lung cancer (NSCLC) comprises ~80% of lung cancer diagnoses; in White patients, around 10% of NSCLC cases are epidermal growth factor receptor mutation-positive (EGFRm+). Head-to-head clinical trials have demonstrated superior efficacy with second-/third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) versus first-generation EGFR TKIs in EGFRm+ NSCLC. Data from routine clinical practice are necessary to confirm that clinical trial findings are transferable to real-world populations.

Methods:

In NCT02047903, a prospective non-interventional study in Germany, patients with EGFRm+ NSCLC received first-line afatinib until disease progression or intolerable adverse events. Key objectives were progression-free survival (PFS) rate at 12 months, objective response rate (ORR) and overall survival (OS). Safety/tolerability was also assessed.

Results:

Of 152 patients, 106 (69.7%) were female, 20 (13.1%) patients had an uncommon EGFR mutation and 51 patients (33.6%) had brain metastases. A starting dose of <40 mg was received by 39 (25.7%) patients. Overall, the 12-month PFS rate was 50.2% while the median PFS was 12.2 months. The ORR was 74.6% and the median OS was 30.4 months. In patients with brain metastases and uncommon mutations, the median PFS was 10.5 and 10.7 months, and the ORR was 77.3% and 83.3%, respectively. Treatment effectiveness was similar in patients with a starting dose of <40 mg (median PFS: 16.4 months; ORR, 81.3%) and a starting dose of 40 mg (median PFS: 10.8 months; ORR, 72.1%). Adverse drug reactions were manageable and consistent with the known afatinib safety profile.

Conclusion:

The results support clinical trial data for afatinib in routine clinical practice, including in patients generally excluded from clinical trials. Outcomes were positive in patients with uncommon EGFR mutations and in those with brain metastases. Treatment benefit was also seen in patients receiving a <40 mg afatinib starting dose, supporting patient-tailored dosing.